I currently own a 2015 Laramie 1500 with the 5.7 Hemi. I have over 30,000 miles and haven't had a single issue. I just change the oil. I have the truck 13 months. I carry approximately 500 lbs of tools everyday and average 16.7 mpg ( highway/ city ) . On the highway I get 19-23 depending on how...